Case converter — UPPER, lower, Title Case and code cases
Convert text to UPPER, lower, Title Case, Sentence case, camelCase, snake_case, kebab-case and more, each with one-click copy.
- Runs in your browser
- Files are never uploaded
- Free, no account
Each line is converted on its own, so a list of headings or variable names all convert at once.
- Characters
- 0
- Words
- 0
- Lines
- 0
Title Case keeps articles, conjunctions and short prepositions lowercase unless they start or end the line, and leaves existing acronyms such as NASA or API untouched.
0 characters · Headline style — short words such as “of” and “the” stay lowercase.
How to convert text case
- Paste your text — one line or a thousand. Each line is converted independently, so a list stays a list.
- Scan the preview grid: every style shows what your first line becomes.
- Press Copy on any style to put the full converted text on your clipboard, or select a style to see the whole result and download it.
- Use “Use as input” to chain conversions — for example lowercase everything first, then apply Title Case for a clean, consistent headline.
The thirteen cases, and when each one is right
| Style | Example | Use it for |
|---|---|---|
| UPPER CASE | USER PROFILE SETTINGS | Warnings, short labels, legal headings |
| lower case | user profile settings | Normalising input, email addresses, tags |
| Title Case | The Art of the Deal | Headlines and page titles in editorial style |
| Capitalised Each Word | The Art Of The Deal | Names, menu labels, table headers |
| Sentence case | User profile settings | UI copy, buttons, modern documentation |
| camelCase | userProfileSettings | JavaScript, Java and Swift variables |
| PascalCase | UserProfileSettings | Class names, React components, C# members |
| snake_case | user_profile_settings | Python, Ruby, SQL columns |
| kebab-case | user-profile-settings | URLs, CSS classes, file names |
| CONSTANT_CASE | USER_PROFILE_SETTINGS | Environment variables, enum members |
| dot.case | user.profile.settings | Config keys, namespaces, i18n paths |
| aLtErNaTiNg | uSeR pRoFiLe | Sarcasm on the internet, nothing else |
| iNVERSE cASE | uSER pROFILE | Repairing text typed with Caps Lock on |
How Title Case is decided
Real title case is not “capitalise every word”. The convention shared by AP, Chicago and most house styles is: capitalise the first and last word, capitalise everything else, but leave articles (a, an, the), coordinating conjunctions (and, but, or, nor) and short prepositions (at, by, for, in, of, on, to, with) lowercase when they fall in the middle. This converter follows that rule, always capitalises the word after a colon, dash or question mark, capitalises both halves of a hyphenated compound, and leaves existing all-caps acronyms such as NASA, API or PDF exactly as you typed them.
Sentence case is the opposite philosophy and has quietly won in software: capitalise only the first word and any proper nouns. It is easier to read at small sizes, easier to translate, and it is what Apple, Google and GOV.UK all specify in their design systems. The converter lowercases everything, capitalises the first letter after each sentence-ending punctuation mark or line break, and restores the standalone pronoun “I”.
Identifier cases and how words are detected
Converting to camelCase or snake_case needs the text split into words first. The splitter
handles all the awkward cases: it breaks on spaces, hyphens, underscores and dots; it breaks
between a lowercase letter and a following capital (userName →
user name); it correctly handles runs of capitals followed by a word
(HTTPResponse → http response); and it separates letters from digits
(address2 → address 2). That means you can paste an identifier in
any convention and convert it to any other.
Practical uses
- Fixing accidental Caps Lock — one click of iNVERSE cASE restores a whole paragraph.
- Renaming code across conventions — paste a column of field names and get the snake_case or camelCase equivalents in one go.
- Cleaning imported data — spreadsheet exports full of SHOUTING NAMES become properly capitalised in seconds.
- Headline consistency — apply the same title rules across an entire content calendar.
- Environment variables — turn a settings list into CONSTANT_CASE keys ready for a
.envfile.
Nothing leaves your browser
Conversion runs locally, so pasting internal field names, unreleased headlines or customer data carries no upload risk. Large inputs are processed in chunks with the interface kept responsive between them, so even a multi-megabyte file converts without freezing the tab.
Questions
What is the difference between Title Case and Capitalise Each Word?
Title Case follows editorial style: articles, conjunctions and short prepositions such as "a", "of" and "the" stay lowercase unless they open or close the line. Capitalise Each Word capitalises everything, which is what you want for names and menu labels.
Are acronyms preserved?
Yes. A word that is already fully uppercase and longer than one letter — NASA, API, PDF — is left alone by Title Case and Capitalise Each Word, instead of being flattened to "Nasa".
How does it handle multi-line input?
Each line is converted independently, so a list of headings becomes a list of headings and a list of labels becomes a list of separate camelCase or snake_case identifiers rather than one giant name.
What is iNVERSE case for?
It swaps the case of every letter, which instantly repairs a sentence typed with Caps Lock on while holding Shift — the classic "hELLO wORLD" problem.
Does it work offline?
Yes. All the conversion logic ships with the page, so once it has loaded you can disconnect and it keeps working. Nothing you paste is ever transmitted.